The invention resides in an apparatus for assessing an object disposed on a movable carrier, which apparatus includes an image recording device for surveying the object.
Such an apparatus is well-known in the state of the art and is used among others for the determination of a location and/or position of work pieces or construction components in automatic assembly equipment and also in the application of electronic components to conductor plates.
In particular during the application of electronic circuit components to conductor plates, it is very important that the components are applied to the conductor plates in an accurate position. To this end, the position and location of a respective component relative to the gripper by which the component is applied to the conductor plate is determined.
By determining the position and the location of the building component in the gripper, the gripper can be so adjusted that the component is deposited on the conductor plate in an accurate position. The gripper is adjusted generally on the basis of coordinates determined by means of a camera which includes an image recording element in the form of a semiconductor chip and a lens. Based on the coordinates, by a comparison of the coordinates with the respective desired coordinates, the position adjustment required for the gripper can be calculated.
For determining the location and position of the building component in the gripper, the gripper, after taking on the building component from a storage arrangement, moves past a camera. The camera detects the location and the position of the component and supplies the respective coordinate values to a control unit which then evaluates the data. If the building component is not disposed exactly in its desired location and position on the gripper, correction values are calculated in the control unit by which the gripper deposits the building component on the conductor plate in a correspondingly displaced manner.
Even though electronic building components or, respectively, work pieces can be delivered by the gripper in an essentially accurate position and location, the accuracy of the apparatus can still be improved: Because the building components or respectively, workpieces move during their detection relative to the camera, depending on the exposure time, fuzzy edges of the building component or respectively, workpiece are recorded. This results in a position or location determination of the building component or work piece which varies in the area of the fuzziness. As a result, the correction values have a correspondingly limited accuracy.
It is the object of the present invention to provide an arrangement of the type as described in the introductory part in such a way that an exact determination of the position, or respectively, location of an object can be achieved even with long exposure time.